import React, { Component,lazy,Suspense } from 'react'
import {NavLink ,Route} from 'react-router-dom'

import Loading  from './Loading'
//  懒加载组件 
const Home =lazy(()=>import('./Home'))
const About= lazy(() => import('./About'))

export default class Demo extends Component {
  render() {
    return (
        <div>
        <div className="row">
            <div className="col-xs-offset-2 col-xs-8">
                <div className="page-header"><h2>React Router Demo</h2></div>
            </div>
        </div>
        <div className="row">
            <div className="col-xs-2 col-xs-offset-2">
                <div className="list-group">
                    {/* 在React中靠路由链接实现切换组件--编写路由链接 */}
                    <NavLink className="list-group-item" to="/about">About</NavLink>
                    <NavLink className="list-group-item" to="/home">Home</NavLink>
                </div>
            </div>
            <div className="col-xs-6">
                <div className="panel">
                    <div className="panel-body">
                        {/*  */}
                        <Suspense fallback={<Loading/>}>
                            {/* 注册路由 */}
                            <Route path="/about" component={About}/>
                            <Route path="/home" component={Home}/>
                        </Suspense>
                    </div>
                </div>
            </div>
        </div>
    </div>
    )
  }
}
